Soluble interleukin-6 receptor to interleukin-6 (sIL-6R/IL-6) ratio in serum as a predictor of high Gleason sum at radical prostatectomy

Approximately 40% of males with low Gleason grade clinically localized prostate cancer (PCa) at biopsy were finally diagnosed with high Gleason grade PCa at radical prostatectomy (RP). Therefore, a more reliable assessment of the Gleason grade prior to RP is required. Readily available modalities such as circulating biomarkers may be useful for this purpose. The aim of this study was to evaluate the ability of preoperative interleukin 6 (IL-6) and its soluble receptor (sIL-6R), as well as urokinase-type plasminogen activator (u-PA), its receptor (u-PAR) and the inhibitor (PAI-1) to predict Gleason score upgrading. A total of 51 PCa patients with biopsy Gleason score <= 7 were studied. IL-6 and sIL-6R, uPA, uPAR and PAI-1 preoperative serum levels were determined. Differences in the median and mean values of the preoperative blood levels of all biomarkers between patients with and without Gleason score upgrading were tested. The prognostic performance of each biomarker was further assessed by means of receiver operating characteristic (ROC) curves. The results showed the sIL-6R and sIL-6R/IL-6 ratio median levels to be significantly higher in patients who had Gleason score upgrading from <= 7 at biopsy to >7 at RP (p=0.024 and p=0.011, respectively). The ROC curve revealed that sIL-6R and the SIL-6R/IL-6 ratio identified subjects at a high risk of upgrading [area under curve (AUC)=0.80 and AUC=0.83, respectively] with similar sensitivity and higher specificity for the ratio. The findings suggest that preoperative sIL-6R and sIL-6R/IL-6 ratio determination in serum are useful as prognostic biomarkers in PCa patients.